Vulcanization of rubber



Patented Nov.,28, 1944 Paul C. Jones and Roger A. Mathes, Akron, Ohio, assignors toThe B. F. Goodrich Company, New York, N. Y., a corporation of New York No Drawing.

1 Claim. 1

This invention relates to the vulcanization of rubber and has as its object to provide a new and effective class of vulcanization accelerators.

We have observed that polynitroaryl esters of. mercaptothiazolines are poor accelerators of vulcanization. We have found, however, that inthe presence of a member of the class consisting of monocarboxylic acids and metallic salts thereof, polynitroaryl esters of z-mercaptothiazolines are excellent accelerators of vulcanization. Any

polynitroaryl esters such as the ZA-dinitrophenyl;

2,6- dinitro 4-chlorophenyl; picryl; 2,6 -dinitro-4-. methylphenyl; 2,6-dinitro naphthyl; .ZA-dinitro anthryl; and ZJT-dinitrc phenanthryl esters of 2- mercaptothiazoline or its substitution products in which one or more of the hydrogens on the carbon atoms are replaced by aliphatic or aromatic groups as disclosed in our copending application Serial No. 255,358, filed February 8, 1939, may be employed in rubber compositionsin accordance with the method of this invention. In its broadest scope, accordingly, the invention consists in vulcanizingrubber in the presence of a monocarboxylic acid or metallic salt thereof and a compound containing the structure wherein A stands for a polynitro aryl group.

Asa specific embodiment of my invention, compositions containing rubber 100. parts by weight,

i that all manner of rubber goods includingpneumatic and solid rubber tires, tubes, hose, belting, packing,boots andshoes, surgical rubber goods, l

. seamless dipped rubber articles, etc., may be vul canized in the presence of the accelerators herein described. The accelerator may be incorporated in the rubber by masticatiolimillingor any simi- Application February 8, 1959, f Serial No. 255,559

other alkali, alkaline earth, and heavy metals may be employed inplace of the materials .used

in the specific examples. While the lower fatty acids may be employed if desired, it is preferable to employ their metallic salts, zinc acetate for instance, which are solids. Acids or their metallic salts may be present in any desired proportions, even small amounts usuallyhaving a beneficial effect. For thebest results however, they should be included in the compositions in amounts varying from 1 to 5% or more.

It is a remarkable and unusual property of the, materials of thisinvention that they are activated. 1 by such materials as benzoic acid and salicylic acid which are widely used retarders for. other,

accelerators. Thisunexpected result indicates that mercaptothlazolines'possessproperties not shared by otheraccelerators of vulcanization.

Although the use of the accelerators of this invention has beendescribed in detail in connection withyspecific rubber compositions, itwillbe evident that this invention is applicable to rub ber compositions of the. most varied nature, and

lar process, or in the case of latex, rubber cement, or any other natural or artificial disperzinc oxide 5 parts, sulfur 3.5 parts, and 1 part of I ZA-dinitrophenyl ester of 2+mercaptothiazoline were vulcanized both inthe absence of and in the presence of 3 partsof lauric acid. The vulcanized compositions had the following properties, T signifying tensile strength at break in lbs/in.

and E signifying. the ultimate elongation in per Without acid With acid Time of cure in minutes at287 F THE E It will be observed that the acid produced a marked improvement in the rate of cure and the 5 properties of the vulcanized product.

tions may be heated in the presence of sulfur or i sion or solution of rubber by simply dissolving or suspending the accelerator therein.

. The vulcanization may be performed in) other y manners than that particularly set forth in the specific examples; specifically, rubber composiselenium in hot air, steam, hot water, etc.

It is ,to be understood that the term rubber is employedin the appended claim in a generic I sense to include c-aoutchouc, balata,gutta percha, 1 latex, rubber isomers, or synthetic rubber wheth er or not admixed with pigments, fillers, softeners, antioxidants, other. accelerators, etc.

While we have herein disclosed specific embodimentsof our invention, we do not intend to limit 1 ourselves solely thereto, for, it willbe obvious to those skilled in the art that many modifications such as using other materials having equivalent Any of the saturated or unsaturated monocar- Y boxylic acids such as caprylic, palmitic, .oleic,

ricinoleic, benzoic, salicylic, toluic, or other like acids or their salts with metals such as lead, tin,

sodium, cobalt, nickel, calcium, magnesium, and

properties and varying the proportions of materials used are within the spirit and scope of the invention as defined in the appended claim. We claim:

The 2,4-dinitrophenyl ester of Z-mercaptothiazoline.

PAUL C. JONES. ROGER. A. MATHES. 

